<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>steps逐帧动画-loading</title>
    <style>
        .dotting {
            display: inline-block;
            min-width: 2px;
            min-height: 2px;
            margin-right: 8px;
            box-shadow: 2px 0, 6px 0, 10px 0;
            animation: dot 4s infinite step-start both;
        }

        @keyframes dot {
            25% {
                box-shadow: none;
            }

            /* 0个点 */
            50% {
                box-shadow: 2px 0;
            }

            /* 1个点 */
            75% {
                box-shadow: 2px 0, 6px 0;
            }

            /* 2个点 */
        }
    </style>
</head>

<body>
    <button>订单提交中<span class="dotting"></span></button>
</body>

</html>